Styrenic Foam Recyclability via Phosphate Stabilizers
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Solution Overview
Problem
Current methods for producing styrenic resin extruded foams struggle to achieve a balance between thermal stability, flame retardancy, and recyclability, often requiring high amounts of flame retardants that are environmentally unfavorable and increase production costs.
Innovation Solution
Incorporating an aliphatic bromine-containing polymer, epoxy compound, polyhydric alcohol partial ester, phenolic stabilizer, and phosphite stabilizer in specific amounts into the styrenic resin foam, along with recycled styrenic resin, to enhance thermal stability and flame retardancy while maintaining recyclability and thermal insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HBCD is used as flame retardant, then flame retardancy is improved, but environmental health is worsened due to accumulation in organisms
Solution Approach 1:
The patent changes the chemical parameter of the flame retardant from HBCD to alternative compounds (tris(1,3-dimethylbutyl) phosphate and/or tris(2-chloroethyl) phosphate), maintaining flame retardancy while eliminating environmental accumulation issues
Solution Approach 2:
The patent uses flame retardants that decompose completely without environmental persistence, replacing the long-lasting HBCD with compounds that do not accumulate in organisms or the environment
2Reliability
If flame retardant amount is increased to achieve required flame retardancy, then flame retardancy is improved, but production cost is worsened
Solution Approach 1:
The patent changes the chemical composition parameter to use phosphate-based flame retardants that provide equivalent flame protection at lower concentrations compared to traditional brominated compounds, reducing both cost and environmental impact
3Reliability
If flame retardant is added in larger amount to achieve intended flame retardancy, then flame retardancy is improved, but moldability is worsened
Solution Approach 1:
The patent changes the chemical parameter to use phosphate ester flame retardants that are more compatible with the resin matrix, providing adequate flame protection without interfering with the molding process and final product quality
4Stability of the object's composition
If stabilizers are added to prevent flame retardant decomposition during recycling, then thermal stability is improved, but flame retardancy is worsened
Solution Approach 1:
The patent uses flame retardant compounds that are inherently stable under recycling conditions (extrusion temperatures up to 250°C) and do not require additional stabilizers, thus maintaining both thermal stability and flame retardancy without compromise
Solution Approach 2:
The patent changes the chemical structure parameter to use phosphate-based compounds with higher thermal stability than traditional brominated flame retardants, eliminating the need for stabilizer additives that would compromise flame retardancy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in a styrenic resin foam with improved moldability, flame retardancy, and thermal insulation properties, meeting JIS A9511 standards and allowing for effective recycling without compromising performance.
Implementation Method 1
extruding the mixture into a low pressure area
Implementation Method 2
extruding the mixture into a low pressure area
Implementation Method 3
efficient decomposition before the styrenic resin decomposes. Polystyrene is known to decompose from around 300°C
Implementation Method 4
an epoxy compound (a), a polyhydric alcohol partial ester (b), a phenolic stabilizer (c), and a phosphite stabilizer (d) as stabilizers in predetermined amounts provides good moldability even when the styrenic resin extruded foam containing the flame retardant and the stabilizers is reduced in volume by thermal shrinking and/or thermal melting and is recycled
Implementation Method 5
reduced in volume by thermal shrinking and/or thermal melting
Implementation Method 6
reduced in volume by thermal shrinking and/or thermal melting
Data Source
AI summary
Provided is a method for recycling a styrenic resin extruded foam. The method includes extrusion-foaming a styrenic resin containing 1 to 75% by weight of a recycled styrenic resin that has been reduced in volume by thermal shrinking and/or thermal melting of a styrenic resin foam and a foaming agent to yield a styrenic resin extruded foam. The styrenic resin extruded foam contains an aliphatic bromine-containing polymer as a flame retardant and further contains an epoxy compound (a) in an amount of 4 to 20 parts by weight, a polyhydric alcohol partial ester (b) in an amount of 0 to 20 parts by weight, a phenolic stabilizer (c) in an amount of 4 to 20 parts by weight, and a phosphite stabilizer (d) in an amount of 0 to 0.9 parts by weight, relative to 100 parts by weight of the flame retardant, as stabilizers.